Model systems for the study of carcinogenesis in cultured human bronchus and peripheral lung are being developed. Explants of human bronchus and peripheral lung have been maintained in culture for periods of 3 months and 25 days respectively. The metabolism of chemical carcinogens is being investigated in these tissues. Attempts are being made to culture normal human bronchial epithelial cells in a feeder layer of X-irradiated human lung fibroblasts. It is anticipated that these model systems will be useful for; 1) Identification of environmental carcinogens for bronchus and peripheral lung; 2) Determination of the metabolic pathways for carcinogens in these tissues; 3) Identifying host factors determining susceptibility to chemically induced lung cancer; and 4) Evaluating new methods of prophylactic intervention in populations at high risk of developing lung cancer. BIBLIOGRAPHIC REFERENCE: Barrett, L., McDowell, E., Harris, C., and Trump, B.: Studies on ischemic cell injury: X. Reversal of ischemic cell injury in hamster trachea and human bronchus by organ culture. Beit. Pathol., 1977, In press.